Electric wave-transmitting means



Dec. 27, 1927.

W. S. GORTON ELECTRIC WAVE TRANSMITTING MEANS Filed Aug. 16, 1922Patented Dec. 27, 1927.

UNITED. STATES WILLIAM S. GORTON,

PATENT OFFICE.

OF EAST ORAN GE, NEW JERSEY, ASSIGNOB TO WESTERN ELEC- TRIO COMPANY,INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

ELECTRIC WAVE-TRANSMITTING MEANS.

Application filed August 18, 1922. Serial 1T0. 582,112.

This invention relates to electric wave transmitting apparatus,especially push-pull electron discharge amplifier circuits, and aims toprovide apparatus and circuits wh ch 5 will avoid the use oftransformers and efliciently transmit currents of low frequency, andwill in the case of the push-pull amplifier, obviate any necessity forinsulating the amplifier batteries from ground.

The push-pull amplifier circuit, shown for instance in United Statespatent to Colpitts, No. 1,128,292, February 16, 1.915,, electric waveamplifier, has a transformer coupling in order to apply to the grids oftwo tubes voltages equal in amount but diiferin in phase by 180. It isat times undesirableto use transformer coupling in amplifiers,especially where currents of very low or very high frequencies are to beamplified. With an ordinary push-pull circuit, whenever one A side ofthe line is grounded, if-a non-inductive coupling such as acondenser-resistance or straight resistance coupling, instead of atransformer coupling, is used between the line and theamplifier, thecathodes of the tubes cannot be grounded as usual, since there wouldthen be a short circuit from the ground at-the cathodes to the ground onthe line. Thus, with such a circuit there is no alternative to groundingthe grid of one of the tubes, which necessitates the obviously"undesirable course of insulating various batteries, or their equivalent,from ground.

In accordance with the invention a three electrode electron dischargetube circuit, arranged to give zero amplification, is connected incircuit between the line and the input circuit of one of the amplifiertubes of a push-pull amplifying stage, for the purpose of shifting thephase of the line voltage 180 'and thus providing the proper phase.

difference between the voltages applied to the the invention.

grids ofthe two amplifying tubes. Thus,

second stage is to be a push-pull stage to avoid distortion which wouldotherwise occur because of the large amount of power handled by thesecond stage. In this case 1t 13, as usual, desirable that the cathodeof the amplifying tube of the first stage be grounded, and this means,even if there is no ground on the line outslde of the amplifier, oneside of the circuit feeding the push-pull stage is grounded if the fullline voltage is applied to the amplifymg tube of the first stage througha nonmductive coupling, or in other words, if the first stageisnon-inductively coupled to the line and is not a push-pull stage.

The drawing s ows one embodiment of As 'shown' in the drawing, l1ne 1andan outgoing line du'ctively coupled through a an incoming 3 arenon-intwo stage amplifier 5, the second stage of which comprises tubes 7and 9 connected in push-pull relation, the first stage comprising anamplifying tube 11 and a phase reversin tube 13. The output voltage oftube 11 is applied across the grid and filament of tube 7 through thecondenser-resistance coupling comprising condenser 15 and resistance 17.The output voltage of tube 11 is also applied across the input leadswhich has its output leads connected to the gr d and filament of tube13. A condenser 21 in the input lead of which is connected to the plateoftube 11 prevents flow of direct current from the B attery 23 of theamplifier 5 to the grid of tube 13. Plate current for tube 11 1ssupplied from battery 23 through an impedance 25 which is preferably anon-inductive re: sistance. Similarly, battery 23 supplies plate currentfor tube 13 through resistance 27.

The output voltage of tube 13 is applied across the grid and filament oftube 9 through the condenser resistance coupling comprising a condenser29 and a resistance 31. The output voltage of the second stage of theamplifier, that is, the output voltage of the push-pull stage comprisingtubes 7 and 9, is applied to line 3 through the condenser resistancecoupling comprising condensers 33 and 35 and non-inductive resistance 37and 39. Plate current for tube 7 is of course, that of a potentiometer19 the potentiometer supplibd from battery 23 through resistance 37; andplate current for tube 9 is supplied from battery 23 through'resistance39.

The adjustment of potentiometer 19 is such that the voltage applied tothe input circuit of the tube 9 is equal, though opposite in phase, tothe voltage applied to the nput circuit of the tube 7.

The cathodes of all of the tubes are preferably grounded, as shown, toreduce the capacity to ground of the connecting wires and therebydecrease the tendency of the repeater to sing.-

Preferably, condensers 21 and 29 shouldeach have twice the capacity ofcondenser 15, since condensers 21 and 29 are serially interposed betweenthe plate of tube 11 and the rid of tube 9. T e impedances of condensers15, 21 and 29 should be small compared with the im edances ofresistances 17, 25, and 31 in or- Ber that the phase of the voltagedelivered by tube 11 may be changed by 180 degrees with ahigh degree ofaccuracy. It is particularly advantageous to employ this phase shiftingexpedient in the voltage-am lifying stages of an amplifier, where theistortion introduced by the tubes is much less than it is in the powerstages. Thus, in the drawing, the first amplifying stage, comprisingtubes 11 and 13, may well be a voltage amplification stage, and thesecond stage, comprising.tubes '7 and 9, may well be a poweramplification-stage.

The invention claimed is:

1. The combination with a push-pull amlifier comprising two amplifyingelements aving an input circuit including portions individual to saidelements and a grounded portion symmetrically related to said elements,of an unsymmetrically grounded line and non-inductive means for couplingsai line to said individual portions of said input circuit.

2. Aline, two three-electrode electron discharge tubes each having agrounded cathode, and a non-inductive coupling means for applying theundivided voltage of the line to the cathode and the control electrodeof one of said tubes and for applying the undivided voltage of the linein reversed phase to the cathode and the control electrode of the othertube.

3. A system comprising two electron discharge amplifiers connected inpush-pull relation, an electron discharge tube having an output circuitand a control circuit,"

means for supplying electromotive force waves to said control circuitand one of said amplifiers in parallel, and means connecting said outputcircuit to said other amplifier.

4. A system comprising an electricwave transmitting ap aratus having adivided input circuit, a p ase chan 'in'g device, means for supplying,electromotive force waves to circuit of one of said means connectingsaid output circuit to another division of'said input circuit.

6. An amplifier circuit comprising a first stage and a' second stage,said second stage comprising two electron discharge tubes connected inpush-pull relation and said first stage comprising an electron dischargeamplifying tube, said circuit also com rising a phase reversingthree-electrode e ectron discharge tube, means connecting theoutputcircuit of said amplifying tube to the input pushull tubes and the inputcircuit of said p ase reversing tube in output circuit of said phasereversing tube to the input circuit of said other push-pull tube.

7. A line, three three-electrode electron dlscharge amplifying tubes,each having a grounded cathode, a non-inductive coupling means forapplying the voltage of the line to one of said tubes, and anon-inductive coupling means for applying the output voltage of said onetube to the cathode and control electrode of another of said tubes andfor applying said output voltage in reversed phase to the cathode andcontrol electrode of the remaining tube.

8. In combination, a line having one side grounded, a pair ofthree-element space discharge devices connected in push-pull relationand having their cathodes both connected to ground, input terminals forsaid devices, and a non-inductive coupling connecting said line to theinput terminals of said devices, said coupling including noninductivemeans for producing a 180 difference in phase in the line voltages'applied to theinput terminals of the res ective parallel, and meansconnecting the space discharge devices, whereby said evices are adaptedto amplify electrical variations received over said line.

9. A line, two three-electrode electron tubes each having a groundedcathode, and a non-inductive coupling means for transferring voltagebetween two electrodes of one of said tubes and said line withoutsubstantial phase change, and for transferring voltage between thecorresponding two electrodes of the other tube and the line with phasereversal.

10. A system comprising two electronic amplifiers connected in push-pullrelation,

connecting one division of said circuit and said phase changing device,in part llel, to a line, and means connecting the other of saiddivisions and said phase changing device.

In witness whereof, I hereunto subscribe my name this 8th day of August,A. D..

WILLIAM S. GORTON.

